avoid duplicate code in compression dictionary creation

Author: sokra

turbopack/crates/turbo-persistence/src/static_sorted_file_builder.rs

@@ -35,7 +35,7 @@ const AMQF_FALSE_POSITIVE_RATE: f64 = 0.01;
 const KEY_COMPRESSION_DICTIONARY_SIZE: usize = 64 * 1024 - 1;
 /// The maximum bytes that should be selected as key samples to create a compression dictionary
 const KEY_COMPRESSION_SAMPLES_SIZE: usize = 256 * 1024;
-/// The minimum bytes that should be selected as keys samples. Below that no compression dictionary
+/// The minimum bytes that should be selected as key samples. Below that no compression dictionary
 /// is used.
 const MIN_KEY_COMPRESSION_SAMPLES_SIZE: usize = 1024;
 /// The bytes that are used per key entry for a sample.
@@ -147,12 +147,10 @@ pub fn write_static_stored_file<E: Entry>(
 }
 
 fn get_compression_buffer_capacity(total_key_size: usize) -> usize {
-    let mut size = 0;
-    if total_key_size >= MIN_KEY_COMPRESSION_SAMPLES_SIZE {
-        let key_compression_samples_size = min(KEY_COMPRESSION_SAMPLES_SIZE, total_key_size / 16);
-        size = key_compression_samples_size;
+    if total_key_size < MIN_KEY_COMPRESSION_SAMPLES_SIZE {
+        return 0;
     }
-    size
+    min(KEY_COMPRESSION_SAMPLES_SIZE, total_key_size / 16)
 }
 
 /// Computes compression dictionaries from keys of all entries
@@ -162,10 +160,11 @@ fn compute_key_compression_dictionary<E: Entry>(
     total_key_size: usize,
     buffer: &mut Vec<u8>,
 ) -> Result<Vec<u8>> {
-    if total_key_size < MIN_KEY_COMPRESSION_SAMPLES_SIZE {
+    let key_compression_samples_size = get_compression_buffer_capacity(total_key_size);
+    if key_compression_samples_size == 0 {
         return Ok(Vec::new());
     }
-    let key_compression_samples_size = min(KEY_COMPRESSION_SAMPLES_SIZE, total_key_size / 16);
+
     let mut sample_sizes = Vec::new();
 
     // Limit the number of iterations to avoid infinite loops